System and method for displaying images

ABSTRACT

System and method for simultaneous display of multiple images using a single light modulator array. A preferred embodiment comprises a light source that produces a light with desired spectral characteristics, a color filter optically coupled to the light source, and an array of light modulators optically coupled to the color filter. The color filter filters light from the light source to produce light of desired wavelengths and the array of light modulators simultaneously displays multiple images onto a display plane. Portions of the array of light modulators are designed so that each portion can independently display an image and the light source provides needed light to display the image.

TECHNICAL FIELD

The present invention relates generally to a system and a method fordisplaying images, and more particularly to a system and a method forthe simultaneous display of multiple images using a single lightmodulator array.

BACKGROUND

In certain applications, there is a desire to display two (or more)images onto a single display plane of a display system. For example, inthe projection of three dimensional (3-D) images using stereoscopy, twocomponent images of a single three dimension image are displayed on thesingle display plane using polarized light with orthogonalpolarizations. Audiences using special optical devices, such as 3-Dglasses, can cancel out one of the two images per eye can then see asingle 3-D image on the display plane. Additionally, it is possible toreduce color flicker and color banding on a display system if two (ormore) images, each being displayed with a different colored light, weredisplayed simultaneously on a single display plane. Each of the imagescontains color image data from a single image being displayed by thedisplay system. For example, at a given time, a first image may containgreen color image data and a second image may contain blue color imagedata, whereas at some other time the images displayed may contain blueand red color image data or red and green color image data. In athree-color display system, it may be possible to display image data forall three colors.

With reference now to FIG. 1, there is shown a diagram illustrating adisplay system 100, wherein the display system can display two imagessimultaneously on a single display plane 105. In order to display twoimages onto the single display plane 105, the display system 100 canmake use of two arrays of light modulators, with spatial lightmodulators (SLM) being used as light modulators. The diagram shown inFIG. 1 illustrates the display system 100 making use of a particularimplementation of the array of light modulators referred to as a digitalmicromirror device (DMD). A DMD is an array of positional micromirrorsthat can reflect light from a light source onto the display plane 105with the position (state) of the individual micromirrors being dependentupon the value of the image data being displayed. For example, if theimage data being represented by a positional micromirror indicates thatlight should be placed onto the display plane 105, then the positionalmicromirror will be moved into a position so that light from a lightsource will reflect off the positional micromirror onto the displayplane 105.

The diagram shown in FIG. 1 illustrates two DMDs, a first DMD 110 and asecond DMD 111 in the display system 100. A light source 115 and a lightsource 116 can be used to provide the light needed to project the imagedata onto the display plane 105. A color filter 120, used in conjunctionwith the light source 115, and a color filter 121, used in conjunctionwith the light source 116, can be used to filter light provided by thelight source 115 and light source 116 to provide necessary colors, suchas red, blue, and green in a three-color display system. Although shownin FIG. 1 as being two distinct light sources, similar lightingperformance can be achieved by using a single light source and a lightsplitter (not shown) that can split the light from the single lightsource into two light beams. The display system 100 shown in FIG. 1displays significant components used in the display system 100, but forsimplicity purposes, may leave out components that are required forproper operation, such as integrating rods, relay optics, beam shapers,and so forth.

If the display system 100 is to be used to project 3-D images usingstereoscopy, the light source 115 and the light source 116 can beconfigured to produce light with orthogonal polarizations with respectto one another. If the display system 100 is to be used to projectimages with reduced color flicker and banding, then the light source 115and the light source 116 can be configured to produce different coloredlights.

The display system 100 can be formed from two separate projectorsystems, with the DMD 110 and the light source 115 forming one projectorsystem and the DMD 111 and the light source 116 forming anotherprojector system. Alternatively, both the DMD 110 and DMD 111 and thelight source 115 and the light source 116 can be contained within asingle projector system. Although shown as a display system comprised oftwo separate projector systems or a single projector system with twoDMDs, it is possible to make use of more than two separate projectorsystems or DMDs. For example, in a display system that makes use ofthree component colors, such as red, green, and blue, it is possible tocreate three separate projector systems with one separate projector foreach of the three component colors. This can be extended to an evenlarger number of projectors, such as in a display system that makes useof more than three component colors.

One disadvantage of the prior art is that with more than one separateprojector or DMD, maintaining good alignment of the individual pixelscan be very difficult. A small bump to the display system can result inmisalignment of the images produced by the display system. Therefore,expensive optical components and regular calibration must be doneregularly to ensure that the images remain aligned. Furthermore, sinceseparate projectors or DMDs are used, differences in thermal expansionmay result in a misalignment of the images that occurs only after thedisplay system has been powered for a period of time.

Another disadvantage of the prior art is that the optics required tocombine the images from the separate projectors or DMDs can beprohibitively expensive. Therefore the display systems that make use ofseparate projectors or DMDs are typically too expensive for all buthigh-end and commercial installations.

SUMMARY OF THE INVENTION

These and other problems are generally solved or circumvented, andtechnical advantages are generally achieved, by preferred embodiments ofthe present invention which provides a system and a method simultaneousdisplay of multiple images in a display system using a single lightmodulator array.

In accordance with a preferred embodiment of the present invention, amicro-electromechanical device with an array of light modulators isprovided. The device includes a first subset of light modulators and asecond subset of light modulators. Each light modulator in the firstsubset of light modulators modulates light along a first axis ofreflection, while each light modulator in the second subset of lightmodulator modulates light along a second axis of reflection.

In accordance with another preferred embodiment of the presentinvention, a display system is provided. The display system includes alight source, a color filter that is optically coupled to the lightsource, and an array of light modulators that is optically coupled tothe color filter. The array of light modulators simultaneously displaysmultiple images onto a display plane with light from the light sourceused to display each image.

In accordance with another preferred embodiment of the presentinvention, a method for simultaneously displaying multiple images with asingle array of light modulators is provided. The method includesproviding a first light along a first light path to illuminate an arrayof light modulators and providing a second light along a second lightpath to illuminate the array of light modulators. The first light has afirst set of optical properties and the second light has a second set ofoptical properties. The method also includes setting a first lightmodulator state in a first subset of light modulators and setting asecond light modulator state in a second subset of light modulators. Thefirst light modulator state corresponds to a first set of image data andthe second light modulator state corresponds to a second set of imagedata.

In accordance with another preferred embodiment of the presentinvention, a method for fabricating an array of light modulators on asubstrate is provided. The method includes forming electrical addressingcircuitry on the substrate and forming a first subset of first hingesover a first portion of the electrical addressing circuitry. The firstsubset of hinges has a first axis of rotation. The method also includesforming a second subset of hinges over a second portion of theelectrical addressing circuitry. The second subset of hinges has asecond axis of rotation. The method further includes forming mirrors oneach of the first hinges and each of the second hinges.

An advantage of a preferred embodiment of the present invention is thata single array of light modulators in a display system can be used tosimultaneously display more than one image on a display plane. The useof a single array of light modulators can simplify the optical system inthe display system. A simpler optical system can also be cheaper,therefore, the cost of the display system can be decreased.

A further advantage of a preferred embodiment of the present inventionis that the use of the single array of light modulators cansignificantly reduce the cost of the optics and eliminate the need forfrequent and expensive image alignment procedures. This cansignificantly reduce the operating cost of the display system.

The foregoing has outlined rather broadly the features and technicaladvantages of the present invention in order that the detaileddescription of the invention that follows may be better understood.Additional features and advantages of the invention will be describedhereinafter which form the subject of the claims of the invention. Itshould be appreciated by those skilled in the art that the conceptionand specific embodiments disclosed may be readily utilized as a basisfor modifying or designing other structures or processes for carryingout the same purposes of the present invention. It should also berealized by those skilled in the art that such equivalent constructionsdo not depart from the spirit and scope of the invention as set forth inthe appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention, and theadvantages thereof, reference is now made to the following descriptionstaken in conjunction with the accompanying drawings, in which:

FIG. 1 is a diagram of a prior art display system;

FIG. 2 is a diagram of an exemplary array of light modulators;

FIGS. 3 a and 3 b are diagrams of exemplary arrays of light modulatorsfor use in simultaneously displaying two images, according to apreferred embodiment of the present invention;

FIGS. 4 a through 4 c are diagrams of display systems for simultaneouslydisplaying multiple images, according to a preferred embodiment of thepresent invention;

FIG. 5 is a diagram of a sequence of events in the simultaneous displayof two sets of image data using a display system with a single array oflight modulators, according to a preferred embodiment of the presentinvention;

FIG. 6 is a diagram of a sequence of events in the manufacture of anarray of light modulators, according to a preferred embodiment of thepresent invention; and

FIGS. 7 a through 7 c are diagrams of exemplary light modulator designsand an array of light modulators, according to a preferred embodiment ofthe present invention.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The making and using of the presently preferred embodiments arediscussed in detail below. It should be appreciated, however, that thepresent invention provides many applicable inventive concepts that canbe embodied in a wide variety of specific contexts. The specificembodiments discussed are merely illustrative of specific ways to makeand use the invention, and do not limit the scope of the invention.

The present invention will be described with respect to preferredembodiments in a specific context, namely a display system that cansimultaneously display two images using a single array of lightmodulators, wherein the light modulators are positional micromirrors.The array of light modulators may be a part of a micro-electromechanicaldevice. The two images can enable the use of stereoscopy to display 3-Dimages or the two images may display different color image data from asingle image to help-mitigate color banding, rainbow effect, flicker,and so forth. The use of a color wheel to provide needed colored lightresults in the production of a sequence of colors being used in adisplay system rather than the simultaneous production of all colorsused in the display system. For example, in a three color displaysystem, the color wheel will produce a sequence of colors, for example,red, blue, green, red, blue, green, and so on. The sequence of colors,if not switched at a sufficient frequency, can lead to undesirable imageartifacts, such as color banding or rainbow effects. The invention mayalso be applied in some situations, however, to other display systemsthat make use of other forms of light modulators, wherein the lightmodulators use light reflection to modulate light, such as deformablemirrors. Furthermore, the invention may also be applicable where thereis a desire to display more than two images simultaneously using asingle array of light modulators. For example, a single array of lightmodulators can be used to display three images, wherein each imagecontains color image data for a single image in a three-color displaysystem. Similarly, four simultaneous images can be displayed using asingle array of light modulators to display color image data for asingle image in a four-color display system.

With reference now to FIG. 2, there is shown a diagram illustrating anexemplary array of light modulators 200, wherein the array of lightmodulators is a DMD. The DMD is a micro-electromechanical device and maybe a part of a larger micro-electromechanical device. The micromirrorsin a DMD typically pivot along a single axis (an axis of reflection),switching between one of two positions, with a first position reflectinglight from a light source onto a display plane and a second positionreflecting the light away from the display plane. The diagram shown inFIG. 2 illustrates the array of light modulators 200 with 16 lightmodulators (micromirrors) arranged in a 4×4 array. As shown in FIG. 2,the micromirror 205 pivots about a diagonal axis. The other 15 lightmodulators in the array of light modulators 200 also pivot about thesame diagonal axis (the same axis of reflection). Alternatively, thearray of light modulators is an array of deformable mirrors and thedeformable mirrors in the array of light modulators deform to move lightalong a single axis, with one position along the axis being a displayplane and another position along the axis being a light dump.

In order to simultaneously display multiple images using a single arrayof light modulators, portions of the array of light modulators need tobe able to display image data from each of the images. For example, ifan array of light modulators is divided into two parts, a first part candisplay image data from a first image and a second part can displayimage data from a second image. An additional requirement can be thatthe light needed for each of the images being displayed may bedifferent. For example, the light used to project the two imagesdisplayed in 3-D stereoscopy may need to have orthogonal polarization,while to reduce color flickering and banding, the light used at the sametime must be of different colors. A different light source (or a singlelight source that is split prior to being modulated by the array oflight modulators) may be needed to provide the needed illumination foreach of the images. To keep the light from the different light sourcesdistinct, different optical paths should be used for each of the lights.To optimize optical quality (image quality), the light sources should bearranged to minimize interference. For example, with two light sourcesand the two resulting axes of reflection (reflecting from the reflectivesurface of the light modulators), arranging the light sources 90 degreesorthogonal to each other would minimize interference between the twolight sources, while with three light sources, an arrangement of 120degrees would minimize light interference. When three or more lightsources are used, it may be necessary to reshape the micromirrors usedin the light modulators to enable a tighter packing of the lightmodulators. The tighter packing of the light modulators can minimizelight leaking below the micromirrors and potentially scattering backonto the display plane and decreasing the contrast ratio of the displaysystem. For example, with three light sources, a hexagonal micromirrormay maximize the packing of the light modulators.

However, since a typical design for micromirrors in a DMD permits themicromirrors to move along a single axis that is aligned with themicromirror's axis of reflection, a different arrangement of the lightmodulators in the array of light modulators is needed. The micromirrorsdesigned to reflect light from one light source either onto or away fromthe display plane will need to pivot along an axis that is parallel tothe light source in order to reflect the light either onto or away fromthe display plane.

With reference now to FIGS. 3 a and 3 b, there are shown diagramsillustrating exemplary arrays of light modulators 300 and 350 designedto function with two distinct light sources arranged 90 degreesorthogonal to one another, according to a preferred embodiment of thepresent invention. A single array of light modulators used tosimultaneously display multiple images should be configured so thatlight modulators assigned to display the separate images are relativelyevenly distributed throughout the array of light modulators. Forexample, in an array of light modulators used to simultaneously displaytwo images, a first image should be displayed using ‘even’ numberedlight modulators (or ‘even’ rows, columns, or diagonals of lightmodulators) and a second image should be displayed using ‘odd’ numberedlight modulators (or ‘odd’ rows, columns, or diagonals of lightmodulators). The intent being that the interlaced multiple images willappear superimposed on one another on the display plane and appear as asingle image. If distinct portions of the array of light modulators wereassigned to display the multiple images, then the images would appear onseparate portions of the display plane. For example, in an array oflight modulators used to simultaneously display two images, if a firsthalf portion of the array of light modulators were used to display afirst image and a second half portion of the array of light modulatorswere used to display a second image, then on the display plane, thefirst image would appear on a first half while the second image wouldappear on a second half. The use of lenses and optical processing canpotentially correct this, but would add unnecessary cost and complexityto the overall cost of the display system. Furthermore, the partitioningof the array of light modulator into distinct portions can cause aspectratio problems wherein the dimensions of the portions of the array oflight modulators may not match well with that of the images.

The diagram shown in FIG. 3 a illustrates an array of light modulators300 wherein alternate rows of light modulators are oriented alongdifferent axes of movement. It is possible to arrange light modulatorsin an array of light modulators so that alternating columns of lightmodulators are oriented along different axes of movement. A first row305, for example, can have light modulators (micromirrors), such aslight modulator 306, oriented along a first axis and a second row 310can have light modulators, such as light modulator 311, oriented along asecond axis. As shown in FIG. 3 a, the first axis and the second axisare orthogonal to each other. The array of light modulators 300 can bedesigned by rotating a single design for a light modulator by 90 degreesto align the light modulators along one of the two axes. In the case ofan array of light modulators being a DMD, wherein the reflective surfaceof each light modulator pivots along an axis that is perpendicular tothe hinge, the orientation of the illumination light beams should beorthogonal to the hinge (parallel to the pivot of the reflectivesurface). Although shown in FIG. 3 a as being oriented on the diagonals,any axis of orientation is possible. Therefore, the diagram shown inFIG. 3 a should not be construed as being limiting to the scope orspirit of the present invention.

The diagram shown in FIG. 3 b illustrates an array of light modulators350 wherein alternating diagonals of light modulators are oriented alongdifferent axes of movement. The array of light modulators 300 featureslight modulators in a single row (or column) being aligned along asingle axis. For example, a first diagonal 355 can have lightmodulators, such as light modulator 366, oriented along a first axis anda second diagonal 360 can have light modulators, such as light modulator361, oriented along a second axis, wherein the first axis and the secondaxis are orthogonal to each other. An array of light modulators withalternating diagonals of light modulators containing light modulatorsthat are oriented along the same axes of movement can be designed byrotating alternating adjacent light modulators by 90 degrees. Althoughshown in FIG. 3 a as being oriented on the diagonals, any axis oforientation is possible. Therefore, the diagram shown in FIG. 3 b shouldnot be construed as being limiting to the scope or spirit of the presentinvention.

When more than one image is being displayed by a single array of lightmodulators, a decrease in the image's contrast may be observed. Forexample, with a conventional 12 degree DMD, centroids of light conesproduced when a light modulators is on and when the light modulator isoff are separated by 48 degrees. However, with two light sourcesarranged at 90 degrees to one another, the centroids of light conesproduced when a light modulators is on and when the light modulator isoff are separated by approximately 34 degrees. This decrease inseparation between the centroids can result in a loss in contrast, sincethe light cones are closer together and light from a first light conemay bleed into a second light cone, e.g., due to scatting effects andlight diffraction effects. However, the use of slower optics can regainthe loss in contrast. Alternatively, the use of a 14 degree DMD in placeof the more common 12 degree DMD can improve the separation of thecentroids to about 38 degrees.

When more than two images are to be displayed by a single array of lightmodulators, it is possible to create an array of light modulators byrotating a single design for light modulator by an appropriate amountthat can maximize the separation of the light sources used to illuminatethe array of light modulators, for example, for a three image array oflight modulators, the light modulators should be rotated by 120 degrees.When three or more images are being displayed, a light modulator with arectangular micromirror may not provide optimum performance. Thereforean alternate design of the light modulator may be needed. For example,in a three image array of light modulators, a hexagonal shapedmicromirror may provide better performance than a rectangularmicromirror.

Since the display of more than one image using a single array of lightmodulators effectively decreases the resolution of the images, thequality of the images being displayed by the array of light modulatorsis not as high as if a single image is being displayed by an array oflight modulators with the same device resolution. For example, if a 4×4array of light modulators is used to display two images, each image canhave a resolution that is equal to a 2×4 array of light modulators beingused to display the images.

Optical dithering, a technique wherein a shift (or multiple shifts) ofan image array, for example, an array of light modulators, combined witha display of a slightly shifted version of an image being displayed bythe image array can effectively double the effective resolution of theimage array. For an image array arranged in a rectilinear configuration,four half image element shifts are needed to double the effectiveresolution of the image array, while for an image array arranged in adiamond configuration, a single half image element shift is sufficientto double the effective resolution of the image array. The use ofoptical dithering can increase the image resolution of the multipleimages that are being displayed by the array of light modulators andtherefore can improve a viewing experience by recovering the spatialresolution that was lost by superimposing the interlaced images. Forexample, the array of light modulators 300 shown in FIG. 3 a can beshifted in four, orthogonal, half image element shifts to double theeffective resolution of images being displayed, while the array of lightmodulators 350 shown in FIG. 3 b can be shifted in one half imageelement shift in a direction orthogonal or parallel to diagonals 355 or360 to double the effective resolution of the images being displayed.

With reference now to FIG. 4 a, there is shown a diagram illustrating anexemplary display system 400, wherein two images can be displayedsimultaneously for 3-D stereoscopy purposes, according to a preferredembodiment of the present invention. The display system 400 can includea light source 405 that can provide desired illumination and can be inthe form of an arc lamp, light emitting diodes, lasers, laser diodes,and so forth. Light from the light source 405 can then be made moreuniform by an integrating rod 407. For wide-band light sources, such aslight sources producing white light, a color filter 409, such as arotating color wheel, can be used to filter the light from theintegrating rod 407 and produce a desired color of light. For example,in a three color display system, the color filter 409 can filter thelight to produce light with the colors red, green, and blue. However,the color filter 409 can be also used to produce light with desiredchromatic characteristics for use in display systems with four, five, ormore colors.

Colored light from the color filter 409 can then be split into two (ormore) light beams by a polarizing beam splitter 411. In addition tosplitting the light into two beams, the polarizing beam splitter canalso polarize the light in each light beam. According to a preferredembodiment of the present invention, the light in each light beam ispolarized so that the polarity of the light in a first light beam isorthogonal to the polarity of the light in a second light beam. Thefirst beam of light from the polarizing beam splitter 411 can beprovided to a relay optics/beam shaper unit “A” 413 and the second beamof light from the polarizing beam splitter 411 can be provided to arelay optics/beam shaper unit “B” 415. The relay optics/beam shaper unit“A” 413 and the relay optics/beam shaper unit “B” 415 can provideoptical processing and manipulation of the first beam of light and thesecond beam of light as well as routing the light to a DMD 417, where,depending upon the state of individual light modulators in the DMD 417,the light can be reflected onto a display plane or dumped into a lighttrap (not shown).

An alternative to the display system 400 is possible wherein two (ormore) light sources are used in place of the light source 405. The useof multiple light sources can permit the use of smaller light sourcesthat individually produce less light or the same size light sourcedriven to a lower level. The use of multiple light sources can requirethe use of more than one integrating rod and potentially, multiple colorfilters. However, the polarizing beam splitter 411 may be eliminated andreplaced with a simple polarizer or two (one for light from each of thetwo light sources).

With reference now to FIG. 4 b, there is shown a diagram illustrating anexemplary display system 430, wherein two sets of color image data froma single image can be displayed simultaneously for purposes ofmitigating color banding and flickering, according to a preferredembodiment of the present invention. The simultaneous display of colorimage data for multiple colors from a single image on a display planecan help improve image quality by decreasing color banding and flicker.Depending upon the display system, an image can contain image data forthree, four, five, or more component colors. For example, in a threecolor display system, an image can contain image data for red, green,and blue component colors. According to a preferred embodiment of thepresent invention, a display system, such as the display system 430, cansimultaneously display two sets of color image data from a single image.For example, if the display system 430 is a three color display system,then the display system 430 can display color image data for componentcolors red and green, followed by color image data for component colorsgreen and blue, then color image data for component colors blue and red,and so on.

The display system 430 can include a light source 435 that can providedesired illumination and can be in the form of an arc lamp, lightemitting diodes, lasers, laser diodes, and so forth. Light from thelight source 435 can then be made more uniform by an integrating rod437. A beam splitter 439 can split the light from the integrating rod437 into two (or more) beams of light. The two beams of light from thebeam splitter 439 can be provided to a color filter 441 that may containa single color filter, such as a color wheel that can filter the lightfrom both beams of light or multiple color filters (color wheels), withone color filter for each beam of light. For example, in the case of asingle color wheel, light from a first beam of light may strike thecolor wheel on a first portion of a face of the color wheel (with onecolor) and while simultaneously light from the second beam of light maystrike the color wheel on a second portion (with a different color) of aface of the color wheel. As long as the color wheel is properlydesigned, the light from the first beam of light will be filtered toproduce a first color and the light from the second beam of light willbe filtered to produce a second color, with the first color beingdifferent from the second color. The use of a single color wheel canhelp to reduce the overall cost of the display system 430.

Colored light from the color filter 441 can then be provided to a relayoptics/beam shaper unit “A” 443 and to a relay optics/beam shaper unit“B” 445. The relay optics/beam shaper unit “A” 443 and the relayoptics/beam shaper unit “B” 445 can provide optical processing andmanipulation of the first beam of light and the second beam of light aswell as routing the light to a DMD 447, where, depending upon the stateof individual light modulators in the DMD 447, the light can bereflected onto a display plane or dumped into a light trap (not shown).

An alternate to the display 430 is possible wherein two (or more) lightsources are used in place of the light source 435. A diagram shown inFIG. 4 c illustrates a display system 460 with two light sources 465 and466 are used in place of a single light source. The use of multiplelight sources can enable the use of smaller light sources than requiredfor a single light source display system or the same size light sourcesdriven to a lower light level. For example, an LED light source can bedriven so that a lower light level is produced. Driving the LED lightsource at a lower light level can increase the useful life of the lightsource. Each of the two light sources 465 and 466 can require a separateintegrating rod 467 and 468 and a single color filter 469 that maycontain a single color wheel used in a manner as described above ormultiple color wheels, one per light source. Colored light from thecolor filter 469 can then be provided to separate relay optics/beamshaper units, such as relay optics/beam shaper unit “A” 471 and relayoptics/beam shaper unit “B” 473, that can provide optical processing andmanipulations of the colored light as well as routing of the coloredlight to a DMD 475, where, depending upon the state of individual lightmodulators in the DMD 475, the light can be reflected onto a displayplane or dumped into a light trap (not shown).

With reference now to FIG. 5, there is shown a diagram illustrating asequence of events 500 in the use of a single array of light modulatorsin a display system to simultaneously display a plurality of images,according to a preferred embodiment of the present invention. Thesequence of events 500 describes the use of the single array of lightmodulators to simultaneously display two images on a display plane.However, the sequence of events 500 can be readily extended tosimultaneously display three or more images using a single array oflight modulators. Therefore, the discussion of the sequence of events500 should not be construed as being limiting to either the scope or thespirit of the present invention. Furthermore, the sequence of events 500is not intended to imply temporal sequencing information of any type.For example, a first event displayed (and discussed) before a secondevent does not imply that the first event needs to occur before thesecond event unless specified. Often the two events can occursimultaneously.

The sequence of events 500 can begin with providing a first light on afirst illumination path to an array of light modulators, wherein thefirst light has a first set of optical properties (block 505). Forexample, the first light in the first illumination path may have acertain polarization polarity or a certain color. While the first lighton the first illumination path is illuminating the array of lightmodulators, a providing of a second light on a second illumination pathto the array of light modulators, wherein the second light has a secondset of optical properties, is occurring (block 510). The opticalproperties of the second light in the second illumination path should bedifferent from the optical properties of the first illumination path ora single illumination path would have been adequate. For example, thesecond light may have a different polarization polarity or a differentcolor or both. The providing of the first light and the second light canbe as simple as providing power to a light source, sequentiallyproviding power to a multitude of light sources, or may involve theissuance of a sequence of light control instructions or, for example,the controlled spinning of a wheel, placed in a white light path,containing color filters and/or polarizers to configure a light source(or light sources) to provide light with desired duration, color,polarization, and so forth.

Once the first light of the first illumination path and the second lightof the second illumination path are on and illuminating the array oflight modulators, a first set of image data can be provided to a firstsubset of light modulators in the array of light modulators (block 515).The first set of image data can be used to configure the states of thelight modulators in the first subset of light modulators to properlydisplay the image data on the display plane using the first illuminationpath. Depending upon the application of the display system, the firstset of image data can contain image information for one of two imagesused in 3-D stereoscopy, color image data for a single image, or soforth. As the first set of image data is being provided to the firstsubset of light modulators (block 515), a second set of image data canbe provided to a second subset of light modulators in the array of lightmodulators to configure the states of the light modulators in the secondsubset of light modulators to properly display the image data on thedisplay plane using the second light (block 520). The providing of imagedata to the first subset of light modulators and the second subset oflight modulators can continue until there is no more image data toprovide or the display system is powered off or reset.

With reference now to FIG. 6, there is shown a diagram illustrating asequence of events in the manufacture of an array of light modulators,wherein the array of light modulators comprises light modulators thatbelong to one of two different subsets with all light modulators in asingle subset reflecting light along a single axis of reflection,according to a preferred embodiment of the present invention. Thediagram shown in FIG. 6 illustrates a sequence of events 600 in themanufacture of an array of light modulators. The sequence of events 600describes the events in the manufacture of the array of lightmodulators, with emphasis on the creation of electrical addressingcircuitry, hinges, and reflective surfaces. The manufacture of the arrayof light modulators may involve additional manufacturing events,including events occurring before the events shown in FIG. 6 and eventsoccurring after the events shown in FIG. 6. Although the followingdiscussion focuses on an array of light modulators with two subsets oflight modulators, the sequence of events 600 can be readily applied toarrays of light modulators with three or more subsets of lightmodulators. Therefore, the discussion should not be construed as beinglimiting to either the scope or the spirit of the present invention.

The sequence of events 600 can begin with the formation of electricaladdressing circuitry for individual light modulators in the array oflight modulators (block 605). The electrical addressing circuitry caninclude necessary conductors, capacitors, and so forth, for storingimage data and creating an electrostatic field to tilt each lightmodulator, depending on the specific value of the image data for eachlight modulator. Since each light modulator in the array of lightmodulator belongs to one of two different subsets of light modulators,wherein each light modulator in a subset of light modulator reflectslight along a single axis of reflection, the electrical addressingcircuitry for individual light modulators may need to be properlyoriented based upon the light modulator's axis of reflection.

After forming the electrical addressing circuitry, the hinge supportstructures for the light modulators in the array of light modulators canbe formed (block 610). The hinge support structure can be used toprovide necessary support for a hinge on which a reflective surface usedas the light modulator can pivot. Again, since there are two subsets oflight modulators in the array of light modulators, the hinge supportstructure for each of the two subsets may be different. For example, thehinge support structure for light modulators in the first subset mayhave a different hinge pivot orientation and location when compared withthe hinge support structure for light modulators in the second subset toprovide a different axis of reflection for light modulators in the firstsubset.

Once the hinge support structures for the light modulators have beenformed (block 610), the manufacture of the array of light modulators cancontinue with a formation of hinges for the reflective surfaces for eachlight modulator in the array of light modulator (block 615). The hingesare the actual pivot points for the reflective surfaces, and as with theelectrical addressing circuitry and the hinge support structures, thehinge design can differ depending upon the axis of reflection. Althoughthe hinges may differ depending upon the axis of reflection, a singlehinge design may be used if the hinge design is rotated by an amountsubstantially equal to the difference between the first axis ofreflection for the light modulators in the first subset of lightmodulators and the second axis of reflection for the light modulators inthe second subset of light modulators.

After the formation of the hinges (block 615), the reflective surface ofthe light modulators can be formed (block 620). As discussed previously,the shape of the reflective surface can differ depending upon a numberof subsets of light modulators in the array of light modulators toafford a tight packing of the light modulators. Tight packing of thelight modulators can reduce the spacing between light modulators andyield a higher quality image (by increasing image density), improvecontrast ratio (by reducing scattered light), and enable a smallerphysical size for the array of light modulators (by increasing lightmodulator density), and so forth. For example, with two subsets of lightmodulators, the square reflective surface may provide the tightestpacking of the light modulators, while with three subsets of lightmodulators, a hexagonal reflective surface may provide the tightestpacking of the light modulators.

With reference now to FIGS. 7 a through 7 c, there are shown diagramsillustrating views of exemplary designs for single light modulators anda plan view of an array of light modulators, wherein the array of lightmodulator comprises two subsets of light modulators, with each subsethaving a distinct axis of reflection, according to a preferredembodiment of the present invention. The diagram shown in FIG. 7 aillustrates an exemplary design 700 for a single light modulator. Thedesign 700 for the single light modulator comprises electricaladdressing circuitry 705, hinge support structure 710, a hinge 715, anda reflective surface 720. The design and the orientation of the hingesupport structure 710 and the hinge 715 (as well as the electricaladdressing circuitry 705) can allow the reflective surface 720 to pivotalong a first axis of reflection. For example, as shown in FIG. 7 a, thefirst axis of reflection is parallel to a line from the South-Westdirection to the North-East direction, with the North direction beingoriented directly into the page.

The diagram shown in FIG. 7 b illustrates an exemplary design 730 for asingle light modulator. Similar to the design 700 for a single lightmodulator shown in FIG. 7 a, the design 730 for a single light modulatorcomprises the electrical addressing circuitry 705, the hinge supportstructure 710, the hinge 715, and the reflective surface 720. Theorientation of the hinge support structure 710, the hinge 715, and theelectrical addressing circuitry 705, can permit the reflective surface720 to pivot along a second axis of reflection. As shown in FIG. 7 b,the second axis of reflection is parallel to a line from the North-Westdirection to the South-East direction. The first axis of reflection ofthe design 700 and the second axis of the design 730 are preferablyorthogonal to each other to minimize the interference of lightreflecting from each of the light modulators. The design 730 of a lightmodulator can be created by rotating the design 700 of a light modulatorby 90 degrees. Small changes may need to be made in the design of theelectrical addressing circuitry 705 to ensure that the proper connectionof the electrical conductors is maintained in the rotated design.Additionally, changes may also be required in the shape of thereflective surface 720 to ensure that the reflective surface 720 is freeto move throughout its range of motion. The changes are small in natureand should be readily evident to those of ordinary skill in the art ofthe present invention.

The diagram shown in FIG. 7 c illustrates an array of light modulators750, wherein the array of light modulators 750 comprises nine lightmodulators arranged in a 3×3 grid, according to a preferred embodimentof the present invention. The array of light modulators 750 may be apart of a larger array of light modulators. A first row of lightmodulators 755 shows a row of three light modulators, wherein each lightmodulator, such as light modulator 757 (shown without a reflectivesurface to show underlying structures, such as the hinge and hingesupport structures and electrical addressing circuitry), features thedesign 700 (FIG. 7 a) with a hinge 759 oriented along a line startingfrom the South-West direction and ending at the North-East direction. Asecond row of light modulators 760 shows a row of three lightmodulators, wherein each light modulator, such as light modulator 762,features the design 730 (FIG. 7 b) with a hinge 764 oriented along aline starting from the North-West direction and ending at the South-Eastdirection. A third row of light modulators 765 shows a row of threelight modulators, wherein each light modulator, such as light modulator767, is implemented using the design 700, as are the light modulators inthe first row of light modulators 755.

Although the diagram shown in FIG. 7c illustrates the array of lightmodulators 750 wherein alternating rows of light modulators belong to asingle subset of light modulators, alternate embodiments can havealternating light modulators belonging to a single subset of lightmodulators (resulting in alternating diagonals of light modulatorsbelonging to a single subset of light modulators), alternating columnsof light modulators belonging to a single subset of light modulators,and so forth.

Although the present invention and its advantages have been described indetail, it should be understood that various changes, substitutions andalterations can be made herein without departing from the spirit andscope of the invention as defined by the appended claims.

Moreover, the scope of the present application is not intended to belimited to the particular embodiments of the process, machine,manufacture, composition of matter, means, methods and steps describedin the specification. As one of ordinary skill in the art will readilyappreciate from the disclosure of the present invention, processes,machines, manufacture, compositions of matter, means, methods, or steps,presently existing or later to be developed, that perform substantiallythe same function or achieve substantially the same result as thecorresponding embodiments described herein may be utilized according tothe present invention. Accordingly, the appended claims are intended toinclude within their scope such processes, machines, manufacture,compositions of matter, means, methods, or steps.

1. A micro-electromechanical device having an array of light modulators,the device comprising: a first subset of light modulators, wherein eachlight modulator in the first subset of light modulators modulates lightalong a first axis of reflection; and a second subset of lightmodulators, wherein each light modulator in the second subset of lightmodulators modulates light along a second axis of reflection.
 2. Themicro-electromechanical device of claim 1, wherein the light modulatorsin the first subset of light modulators and the light modulators in thesecond subset of light modulators are distributed substantially evenlythroughout the array of light modulators.
 3. The micro-electromechanicaldevice of claim 2, wherein adjacent light modulators in at least oneplanar axis of the array of light modulators belong to different subsetsof light modulators from each other.
 4. The micro-electromechanicaldevice of claim 3, wherein the at least one planar axis is a row,column, or diagonal of the array of light modulators.
 5. Themicro-electromechanical device of claim 2, wherein adjacent rows,columns, or diagonals of the array of light modulators belong todifferent subsets of light modulators, and wherein each light modulatorwithin a respective single row, column, or diagonal belongs to a singlesubset of light modulators.
 6. The micro-electromechanical device ofclaim 1, wherein the first axis of reflection of the first subset oflight modulators is substantially orthogonal to the second axis ofreflection of the second subset of light modulators.
 7. Themicro-electromechanical device of claim 6, wherein a single designlayout is used for all light modulators in the array of lightmodulators, and wherein a light modulator in the second subset of lightmodulators is rotated by an amount substantially equal to a differencebetween the first axis of reflection and the second axis of reflectionwith respect to a light modulator in the first subset of lightmodulators.
 8. A display system comprising: a light source configured toproduce a light with desired spectral characteristics; a color filteroptically coupled to the light source, the color filter configured tofilter light provided by the light source to produce light of desiredwavelengths; and an array of light modulators optically coupled to thecolor filter, the array of light modulators configured to simultaneouslydisplay multiple images onto a display plane, wherein the light sourceprovides light used to display each image.
 9. The display system ofclaim 8, wherein the array of light modulator comprises: a first subsetof light modulators, wherein each light modulator in the first subset oflight modulators modulates light along a first axis of reflection; and asecond subset of light modulators, wherein each light modulator in thesecond subset of light modulators modulates light along a second axis ofreflection.
 10. The display system of claim 8, wherein each imagesimultaneously displayed by the display system contains image data for adifferent component color of an image, and the display system furthercomprises a beam splitter optically coupled between the light source andthe color filter, the beam splitter configured to split the lightproduced by the light source into a plurality of light beams, whereinthere is one light beam for each image simultaneously displayed.
 11. Thedisplay system of claim 8, wherein two images are simultaneouslydisplayed by the display system, wherein the two images are componentsof a three-dimensional stereoscopic image, and the display systemfurther comprising a polarizing beam splitter optically coupled betweenthe color filter and the array of light modulators, the polarizing beamsplitter configured to split the light produced by the light source intotwo light beams, wherein a first light beam is polarized with a firstpolarization and a second light beam is polarized with a secondpolarization, and wherein the first polarization and the secondpolarization are orthogonal.
 12. The display system of claim 8, whereinthe array of light modulators is an array of micromirrors.
 13. Thedisplay system of claim 12, wherein the array of light modulators is adigital micromirror device (DMD).
 14. The display system of claim 12,wherein the array of light modulators is an array of deformable mirrors.15. The display system of claim 8, wherein each image is displayed usingoptical dithering to increase an effective resolution of the displayedimages.
 16. A method for simultaneously displaying multiple images witha single array of light modulators, the method comprising: providingfirst light along a first light path to illuminate an array of lightmodulators, wherein the first light has a first set of opticalproperties; providing second light along a second light path toilluminate the array of light modulators, wherein the second light has asecond set of optical properties; setting a first light modulator statein a first subset of light modulators in the array of light modulatorscorresponding to a first set of image data; and setting a second lightmodulator state in a second subset of light modulators in the array oflight modulators corresponding to a second set of image data.
 17. Themethod of claim 16, wherein the first subset of light modulatorsreflects the first light onto a display plane depending upon the firstlight modulator state in the first subset of light modulators, and thesecond subset of light modulators reflects the second light onto thedisplay plane depending upon the second light modulator state in thesecond subset of light modulators.
 18. The method of claim 16, whereinthe first light is polarized with a first polarity, wherein the secondlight is polarized with a second polarity, wherein the first polarityand the second polarity are orthogonal, and wherein the first set ofimage data and the second set of image data are components of a threedimensional stereoscopic image.
 19. The method of claim 16, wherein thefirst light comprises a first color of light, wherein the second lightcomprises a second color of light, wherein the first color of light andthe second color of light are different and each color is a subset ofcolors used to display an image, and wherein the first set of image datacomprises image data for the first color of light for the image and thesecond set of image data comprises image data for the second color oflight for the image.
 20. A method for fabricating an array of lightmodulators on a substrate, the method comprising: forming electricaladdressing circuitry on the substrate; forming a first subset of firsthinges over a first portion of the electrical addressing circuitry,wherein the first subset of first hinges has a first axis of rotation;forming a second subset of second hinges over a second portion of theelectrical addressing circuitry, wherein the second subset of secondhinges has a second axis of rotation; and forming mirrors on each of thefirst hinges and each of the second hinges.
 21. The method of claim 20,wherein the first axis of rotation and the second axis of rotation aresubstantially orthogonal.
 22. The method of claim 20, wherein the firstsubset of first hinges and the second subset of second hinges aredistributed substantially evenly throughout the array of lightmodulators.
 23. The method of claim 20, wherein the first hinges and thesecond hinges are formed in alternating rows, columns, or diagonals onthe substrate.